In 1997, the Consultative Committee for Photometry and Radiometry (CCPR) initiated a supplementary comparison of spectral radiance in the wavelength range from 220 nm to 2500 nm (CCPR S1) using tungsten -strip filament lamps as transfer standards. Five National Metrology Institutes (NMIs) took part in the comparison: BNM/INM (France), NIST (USA), NRC (Canada), PTB (Germany) and VNIIOFI (Russia), with VNIIOFI as the pilot laboratory. Each NMI provided the transfer lamps that were used to transfer their measurements to the pilot laboratory. The intercomparison sequence began with the participant measurements, then the pilot measurements, followed by a second set of measurements by the participant laboratory. The measurements were carried out during the time from 1998 to 2002, with the final CCPR report completed in 2008. This paper presents descriptions of measurement facilities and uncertainties of the participants, as well as the comparison results that were analyzed in accordance with the Guidelines for CCPR Comparisons Report Preparation, and a re-evaluation of the results taking into account the instability of some of the transfer lamps. Excluding a few wavelengths, all participants agree to each other within ±1.5 %. The disagreement decreases to approximately ±1.0 % when the anomalous data are excluded from the analysis.
Pub Type: Journals
Comparisons, Spectral Radiance, SI Units